1 Application
Model GL-1A Weir Transducer is applicable to measure the water level of weir notch for the river, pool, water reservoir, dam, etc. It is the device that used for monitoring and measuring the changing of flow. This device adopts the magnetostrictive transducer. It has the advantages as high resolution, high accuracy, high stability, high reliability, short response time, long lifetime, etc.
The main features are: measurement in straight-line, output with resolute position, non-contact continuously measurement, free of abrasion, free of second calibration, no needs to maintain carefully, multi-choice with input-output (could be Voltage/Current analogue or RS485 digital signal), easy for installation, etc.
2 Technical Specifications
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GL-1A
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Measurement Range (mm)
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0～700
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Least Reading
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≤0.2
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Accuracy (F.S)
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±0.1%
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Signal Output
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0～5V、4～20mA、RS485
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Insulation Resistance
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≥50Ω
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3 The Theory of Operating
3.1 Constitution
Model GL-1A Weir Transducer consists of antifouling tube, top lid, magnetostrictive transducer, spirit bubble, cable, etc. (also see Fig.1)
3.2 Mechanism
The transducer mainly consists of the measurement rod, electronic part and the non-contact magnetic float ball. Inside the rod there is magnetostrictive wire (Guide wire). And the measurement rod is made of stainless steel tube that is not magnetic thus the guide wire is reliably protect. During working, the electrical circuit generates an initial pulse and the pulse generates the rotating magnetic field in the direction of the guide wire when it is transferred in the guide wire. And when this magnetic field meets the permanent magnetic field in the floating ball, then magnetostrictive effect generates so that the guide wire will be twisted. This twist is identified by the electronic part and converted further to the corresponding current pulse. By measuring the time different of these two pulses, the measured water level value can be précised obtained.
4 Reading and Calculation
4.1 Reading
Using Model GN-103A Readout Box can directly read the modulus value F manually; using Model MCU-32 Distributed Modularization Automatic Measuring Unit is able to collect data automatically.
4.2 Calculation
△L= K (F－F0)
Herewith,
△L: the changing value of the water level in the weirnotch with the unit of mm;
F: Real time measured value with the unit of F;
F0: Reference value with the unit of F;
K: Transducer coefficient with the unit of mm/F;
4.2.1 If the changing value of water level △L is positive then it means the water level is increased relative to the reference value.
4.2.2 If the changing value of water level △L is negative then it means the water level is decreased relative to the reference value.
4.2.3 In the normal working situation, the temperature influence is very small to the system. The temperature correction coefficient is smaller than the least reading, thus the influence of temperature can be ignored.
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